Mechanical pencil



Dec. 26, 1939. L. J. MOST MECHANICAL PENCIL Filed March 18, 1939INVENTOR I, J flask NEY Patented Dec. 26,. 1939 UNITED STATES PATENToFFic 7 Claims.

My invention relates to mechanical pencils, and is a modification of thepencil disclosed in my pending application, Serial No. 209,739, filedMay The object of the invention is to supply a simple mechanism, formedof few moving parts, for propelling, repelling, expelling andautomatically presenting a new lead to writing position.

Another object of the invention is to provide a mechanical pencil, inwhich the lead itself is a part of the feed mechani m.

A further object of the invention is to provide a pencil, which, whenengaged by the fingers for writing purposes, will always present an edgeof i a lead prism.

In the appended drawing, forming part of this application, Figure 1 is afragmentary elevation, partially in section, of a pencil embodying myinvention.

Figure 2 is an enlarged section on line 22, Figure 1.

Figure 3 is a similar enlarged section on line 3-3, Figure 1.

Figure 4 is a further enlarged section on line 4-4, Figure 3, and

Figure 5 is an enlarged cross-section on line 5-5, Figure 1.

Referring to the drawing, I0 is the pencil barrel or shell terminatingwith a frusto-cone portion H, having an annular groove [2. Fitted in thegroove I2 is an exterior threaded split ring [3, provided at its upperend with a flange M. The peripheral edge of the flange is slightlylarger than that of the adjacent periphery of the frusto-cone portionII. The split ring I3 is retained in the groove l2 by the engagement ofits threads with the threads in the larger end of a hollowconicallyshaped tip 15. The edge of the larger end of the tip abuts against theflange when fully engaging the split ring, and will re volve therewithon the frusto-cone portion ll, although prevented from movinglongitudinally thereof. To remove from or engage the tip with the ring,it is only necessary to grip the edge of the flange l4 exposed on thefrusto-cone portion II, and to turn the tip or flange in the properdirection.

The cylindrical bore l6 of the barrel changes to a pyramidal bore ll oftriangular cross-section as it approaches the frusto-cone portion H ofthe barrel, the truncated end of the pyramidal bore is merged with ahopper l8 of similar crosssection. The hopper leads to a bore 19 oftriangular cross-section formed in the frusto-cone portion H, and it isthe outlet for a lead 24 from the magazine formed by the barrel. Thepyramidal bore ll, the hopper l8, and the bore Hi, all have theircorresponding angles in common planes. v

The cross-sectional size of the bore E9 is corresponding in size to thecross section of the lead 2d that is to move therethroughlongitudinally, it being prevented from turning therein by theangularity of the bore. The triangular bore in the frusto-cone portion Hat its lower end is recessed, as indicated at 26 to accommodate firmlytherein the. upper end of a tubular lead guide 2| of triangularcross-section of same size bore as that of bore 59, and of which itforms a continuation. The lower end of the tubular guide 20 is providedwith prongs 2| formed by cutting away thereat the edges of the tubularguide 20, so that the prongs 2?. are really formed from the sides of thetubular guide 20 and constitutes with the sides; of said guide the meanswhich guide the lead longitudinally, but prevents it from turning.

The prongs 22 enter into the threaded bore 23 formed in the lower end ofthe tip l5, and although positioned therein do not interfere with theturning of the tip and permit the threaded portion thereof to engage theedges of the lead 24 that is being engaged by the prongs within thethreaded bore. The prongs 22 are really the lead guide which permits theextreme end of a lead section to be forced through the threaded bore 23,which forms the die that engages the lead to move it in any desireddirection.

To always present an edge of the lead prism which is used in the pencil,the lower end of the barrel [0, in proximity of the frusto-cone portionH, is provided with tapering flat surfaces 25 increasing in width asthey approach the frustocone portion II. The number of flat surfacescorrespond to the number of flat surfaces the prismatic lead 24 has, inthis particular case, the cross-section is triangular, and thereforethere is only three flat surfaces, as best indicated in Figure 5, andthe flat surfaces formed on the exterior of the shell are parallel tothe fiat surfaces formed on the interior thereof, so that no matterwhich way the pencil is gripped between the fingers, there is always anedge of the prism of a lead in writin position.

I claim:

1. In a mechanical pencil, a barrel having a frusto-cone portionprovided with a lead outlet, said frusto-cone portion having an externalannular groove, a split ring positioned in said groove, a tip secured tosaid ring whereby said tip and ring are free to turn on said frusto-coneportion, said tip having a threaded bore aligning with the lead outlet,and a lead guide of angular cross-section from the lead outlet andentering the threaded bore, so that a lead engaged by the 5 threadedbore is prevented by said means within the bore from turning while it isfree to move longitudinally.

2. In a mechanical pencil, a barrel having a frusto-cone portionprovided with a lead outlet, said frusto-cone portion having an externalannular groove, an exteriorally threaded split ring positioned in saidgroove, a tip threaded to said ring so that the tip and the ring arefree to turn on said frusto-cone portion, said tip having a threadedbore aligning with the lead outlet, and a lead guide of angularcross-section from the lead outlet and entering the threaded bore, sothat a lead engaged by the threaded bore is prevented by said meanswithin the bore from turning while it is free to move longitudinally.

3. In a mechanical pencil, a barrel having a frusto-cone portion havinga lead outlet, said frusto-cone portion having an external annulargroove, an exteriorally threaded split ring positioned in said groove,saidring having at its upper end a flange, the peripheral edge of whichis slightly larger than the periphery of the frustocone portion in theproximity of the flange, a tip threaded on said ring and abuttingagainst the flange, whereby said tip is revolubly mounted with said ringon said frusto-cone portion of the barrel, said tip having a threadedbore in alignment with the threaded outlet, a lead guide of angularcross-section carried by the frusto-cone portion, prongs formed at theend of the guide remote from the frusto-cone portion, said prongs beingpositioned within the threaded bore of the tip.

4. In a mechanical pencil, a barrel having a lead outlet of angularcross-section, a tip having a threaded bore revolubly mounted on thebarrel to engage a lead of same angular cross-section as the leadoutlet, and means within the threaded bore of the tip for engaging thelead therein so that the lead is free therein to be engaged by thethreaded bore, but prevented by said means from turning while it is freeto move longitudinally,

said barrel having as many fiat surfaces at its outer periphery inproximity of the tip as there are faces in the lead outlet.

5. In a mechanical pencil, a barrel having a lead outlet, a tip having athreaded bore revolubly mounted on the barrel, and a lead guide ofangular cross-section at the outlet, said guide having means positionedwithin the threaded bore so that it leaves the threads of the bore freeto engage the edges of a lead passing through the guide in the bore, butprevents the lead from turning in the bore, said barrel having as manyfiat surfaces on its outer periphery, widening towards the tip as thereare faces in the lead guide, the angles formed by the surfaces of thebarrel being substantially coplanar with the angles of the lead guide.

6. In a mechanical pencil, a barrel having a lead outlet of angularcross-section, a tip having a threaded bore revolubly mounted on thebarrel to engage a lead of same angular cross-section as the leadoutlet, and means within the threaded bore of the tip for engaging thelead therein so that the lead is free therein to be engaged by thethreaded bore, but prevented by said means from turning while it is freeto move 1ongitudinally, said barrel having as many fiat surfaces at itsouter periphery as there are faces in the lead outlet, said surfacesbeing so disposed that when gripped for writing purposes the tip willpresent the lead with one of its edges for writing purposes.

7. In a mechanical pencil, a barrel having a lead outlet, a tip having athreaded bore revolubly mounted on the barrel and a lead guide at thelead outlet adapted to engage a lead so that the lead is free to movelongitudinally in the guide, but prevented from turning therein, saidbarrel having as many fiat surfaces on its outer periphery in theproximity of the tip as there are faces in the lead guide, the said flatsurfaces on the periphery of the barrel being so disposed that whengripped for writing purposes the lead fed by the tip will present one ofits edges for writing purposes.

LUCIFER. J. MOST.

